Double-acting, telescopic cylinder assembly



Oct. 19, 1954 J. H. SENG 2,691,963

DOUBLE-ACTING, TELESCOPIC CYLINDER ASSEMBLY Filed Nov. 2, 1951 2Sheets-Sheet 1 INVENTOR James H-SENG ATTORNEKS J. H. SENG 2 Sheets-Sheet2 r 1 1; v II DOUBLE-ACTING. TELESCOPIC CYLINDER ASSEMBLY INVENTOR JAMEsH. Sens ATTORNEYS mm 7 Wm Filed Nov. 2, 1951 Oct. 19, 1954 Patented Oct.19, 1 954 UNITED STATES PATENT OFFICE DOUBLE-ACTING, TELESCOPIC CYLINDERASSEMBLY James H. Seng, Salina, Kans.

Application November 2, 1951, Serial No. 254,500

2 Claims. .1

This invention relates to double-acting, telescopic cylinder assemblies,and more particularly to a double-acting, hydraulic cylinder assemblyhaving telescopically associated parts for increasing the range ofelongation of the cylinder assembly.

It is among the objects of the invention to provide an improvedhydraulic cylinder assembly which includes telescopically associatedparts, so that a large elongation can be obtained in comparison with thecollapsed or retracted length of the assembly; which is hydraulicallyoperated in both expanding or elongating and its collapsing orcontracting movements; which applies fluid pressure to each of thetelescopically associated parts in both directions of movement; whichprovides substantially equal pressure areas on all of the telescopicallyassociated parts; which includes adjustable means for limiting itselongation; which may be installed on various machines such as powershovels, bulldozers, cranes and vehicles; and which is simple anddurable in construction, economical to manufacture, easy to install, andpositive and effective in operation.

Other objects and advantages will become apparent from a considerationof the following description and appended claims in conjunction with theaccompanying drawings, wherein:

Figure 1 is a side elevational view of a bulldozer shovel showing acylinder assembly illustrative of the invention operatively installedthereon;

Figure 2 is a side elevational view on an enlarged scale of thehydraulic cylinder assembly, a portion being broken away and shown incrosssection to better illustrate the construction thereof;

Figure 3 is a cross-sectional view on an enlarged scale on the line 33of Figure 2;

Figure 4 is a transverse cross-sectional view on the line d l of Figure3;

Figure 5 is a fragmentary cross-sectional view on the line 55 of Figure3;

Figure 6 is a transverse cross-sectional view on the line 6-6 of Figure3; and

Figure '7 is a side elevational view of a somewhat modified form ofcylinder assembly, parts being broken away and shown in cross-section tobetter illustrate the construction thereof.

With continued reference to the drawings, the bulldozer scoop or shovelassembly, illustrated by way of example in Figure 1, includes a pair ofspaced apart and substantially parallel booms, one of which is indicatedat I0, disposed one at each side of a tractor, not illustrated. Abulldozer blade I I is secured near its bottom edge to the front ends ofthe booms and is braced in operative position by links, one of which isindicated at I 2, each secured at one end to the blade II at thecorresponding end of the latter and above the front end of thecorresponding boom 10 and secured at its rear end to the upper end of alug I3 projecting upwardly from the corresponding boom at a locationspaced rearwardly from the blade. The link [2 may be made adjustable tovary the inclination of the bulldozer blade as may be desired. Arms, asindicated at M, extend upwardly and forwardly from the upper edge of theblade ll, one at each end of the blade, and a clamshell bucket I5 issecured at its upper edge to the ends of the arms I l for upward anddownward swinging movement relative to the blade II. An arm [6 projectsupwardly from the link 12 at the end of the link remote from the blade II, and this arm is provided with an aperture near its upper end. Arms,as indicated at ll, project upwardly from the bucket l5, one at each endand near the upper edge of the bucket and these arms are also providedwith apertures near their upper ends. Hydraulic cylinder assemblies, asgenerally indicated at l8, are disposed one at each end of the bulldozerblade H and connected between the corresponding arms l6 and I! fortilting or swinging the bucket I5 relative to the blade ll, theseassemblies being connected to the hydraulic system of the associatedtractor and operated by manually actuated valves located convenient tothe tractor operator.

As the hydraulic cylinder assemblies of the present invention may beoperatively mounted on various machines for various purposes, as may bedesired, the above brief description of one exemplary installation isconsidered sufiicient to fully disclose the utility of the device.

The hydraulic piston assembly includes a first cylinder 20 open at one.end and closed at the other, a second cylinder 2| telescopicallyreceived at one end in the open end of the first cylinder, a piston 22surrounding the second cylinder at the end thereof disposed within saidfirst cylinder and slidably engaging the inner surface of the firstcylinder, a packing ring 23 secured in the first cylinder at the openend thereof and slidably engaging the outer surface of the secondcylinder, a piston rod 24 received at one end in the end of the secondcylinder disposed outwardly of the open end of the first cylinder, apiston 25 secured to the piston rod 24 of the cylinder 2|. cylinder 2|adjacent the packing ring 216 and 3 at the end of the latter disposedwithin the second cylinder, and a packing ring 26 secured in the end ofthe second cylinder which is disposed outwardly of the open end of thefirst cylinder and slidably engaging the piston rod.

The first cylinder 20 has an internal diameter greater than the externaldiameter of the second cylinder 2 and the piston 22 comprises an annularbody or ring of elongated, rectangular cross-sectional shape threadedonto an externally screw-threaded portion 21 at the end of the secondcylinder 2| disposed within the first cylinder 2|! and disposed in thecircumferential space between the two cylinders. This piston has atleast one annular groove 28 in its peripheral surface and a sealing ring29 is seated in this groove and engages the inner surface of thecylinder 2|] to provide a fluid-tight seal between the piston and thecylinder 20. The packing ring 23 includes an annular or cylindricalportion 38 disposed in the circumferential space between the cylinders2| and 20 at the open end of the cylinder 22 and an annular flange 3|extending outwardly from the cylindrical portion 3!! over the open endof the cylinder 20. The cylindrical portion-3B is provided withexternaland internal annular grooves, and sealing rings 32 and 33 are seated inthese grooves and respectively engage the inner surface of the cylinder2c and the outer surface of the cylinder 2| to provide fluid-tight sealsbetween the packing ring and these cylinders. An annular collar 34surrounds the cylinder 20 near the open end thereof, and is held inplace on the cylinder by a snap ring 35 seated in a groove provided inthe exterior surface of the cylinder 2|! near the open end of the latterand received in an annular recess provided in the collar 34 around theinner edge of the collar. Flange bolts 36 extend through apertures inthe flange 3| and are threaded into tapped holes in the collar 34 tomaintain the packing ring 23 in place on the cylinder 2|].

The piston 25 has a central aperture therein which receives the reduced,externally screw threaded end portion 31 of the piston rod 24. A washer38 is secured on the piston rod at the inner end of the screw-threadedportion 31 to provide an abutment for the piston 25, and a nut 39 isthreaded onto the screw-threaded portion of the piston rod at the sideof the piston opposite the abutment to maintain the piston on the pistonrod. The piston 25 is provided with an annular groove in its peripheralsurface, and a sealing ring 50 is seated in this groove and slidablyengages the inner surface of the cylinder 2| to provide a fluid sealbetween the piston 25 and the cylinder 2|.

The cross-sectional area of the interior of the cylinder 2| issubstantially equal to the difierence between the cross-sectional areaof the interior of the cylinder 20 and the cross-sectional area of theinterior of the cylinder 2|, so that the pistons 22 and 25 havesubstantially the same effective pressure areas.

The packing ring 26 comprises a cylindrical portion 4| received in theend of the cylinder 2| remote from the piston 22 and having a boreslidably receiving the piston rod 24. This packing ring also includes aflange 42 extending outwardly from the cylindrical portion 4| at one endof the latter and overlying the adjacent end A collar 4'3 surrounds theis held in place on the cylinder 2| by a snap ring M seated in a grooveprovided in the outer surface of the cylinder 2| adjacent the end of thecylinder remote from the piston 22 and received in an annular recess inthe collar 43 extending around the inner edge of the collar. Flangebolts 45 extend through apertures in the flange 42 of the packing ring25 and are threaded into tapped holes in the collar 43 to secure thepacking ring to the cylinder 2|.

The packing ring is provided with external and internal groovesreceiving sealing rings 45 and 41, respectively, which slidably engagethe inner surface of the cylinder 2| and the surface of the piston rod 28 to provide a fluid-tight seal between the cylinder 2| and the pistonrod.

A pair of spaced apart, substantially parallel lugs 48 project outwardlyfrom the end wall 49 of the cylinderzil substantially at the center ofthe end wall, and these lugs are provided with apertures 50 forreceiving a pivot pin to pivotally secure the cylinder 20 to acylinder-supporting portion of an associated mechanism, such as the linkarm I6 in Figure 1. An apertured lug 5| is provided on the end of thepiston rod 24 remote from the piston 25 for pivotally connecting thisend of the piston rod to another portion of the supporting structure,such as the arm on the scoop l5, as shown .in Figure l.

The cylinder 20 is provided with externally screw-threaded, hollowbosses 52 and 53 projecting laterally therefrom, one at each end of thecylinder, and communicating with the interior thereof. These bossesconstitute fluid conduit fittings by means of which fluid pressureconduits, such .as the conduits 54 and 55, are connected at theircorresponding ends to the cylinder '20.

The packing ring .26 is provided with a drilled passage 56 extendingfrom the side thereof to the end of the cylindrical portion 4| of thispacking ring disposed inwardly of the cylinder 2|, and this passage isprovided with a screw-threaded counterbore 51 in its end adjacent theside of the packing ring. A fitting 58 is threaded into the counterbore51 and one end of a branch conduit 59 is secured to the fitting 58. Theconduit 59 is secured at its other end to the adjacent end of theconduit 55 by means of a Y-fitting 60., on leg of which is connected tothe fitting 53 by a conduit 6i which constitutes, in effect, acontinuation of the conduit 55.

With this arrangement, when hydraulic fluid under pressure is suppliedto the cylinder assembly through the conduit 5d and the conduit 55 isconnected to a sump or vent, the piston 22 will be forced outwardly ofthe cylinder 20 away from the end wall 49 of this cylinder, forcing thecylinder 2| outwardly of the cylinder 22, and the piston 25 will beforced along the cylinder 2| in a direction away from the piston 22,forcing the piston rod 24 outwardly of the cylinder 2|. When the piston22 contacts the packing ring 23 and the piston 25 contacts the packingring 26, the maximum elongation of the assembly will have been obtained.

When the conduit 54 is connected to a sump or drain and fluid underpressure is supplied to the conduit 55, the fluid will act between thepiston 22 and the packing ring 23 to force the cylinder 2| inwardly ofthe cylinder 20 until the collar 43 engages the outer end of the packingring 23 and will act between the piston 25 and the, packing ring 26v toforce the piston rod 24 inwardly of the cylinder 2| until the shoulder62 at the inner end of the lug formation 5| on the piston rodcontactsthe outer end of the packing ring 26, the cylinder assembly then beingcontracted to its shortest condition.

In the modified arrangement illustrated in Figure 7, instead of havingthe collars 34 and 43, the flanges on the packing rings and the flangebolts 36 and 45 connecting the packing ring flanges to the collars, thepacking rings for the cylinders 20 and 2!, as indicated at 63 and 64,respectively, have externally screw-threaded, cylindrical portionsreceived in the corresponding cylinders, and the cylinders areinternally screw-threaded to receive the screw-threaded packing rings.The packing ring 63 is provided with an outwardly extending annularflange 65 of polygonal shape to receive a wrench for threading thepacking ring 63 into and out of the cylinder 20 and the packing ring 64is provided with an outwardly projecting annular flange 66 of polygonalshape for receiving a wrench to thread the packing ring 64 into and outof the cylinder 2|. The packing ring 63 is provided with two spacedapart, internal grooves receiving sealing rings 61 and 68, respectively,which sealing rings slidably engage the outer surface of the cylinder 2|and the packing ring 64 is provided with two spaced apart, internalgrooves receiving sealing rings 69 and which slidably engage the surfaceof the piston rod 24. In the arrangement illustrated in Figures 2 to 6,inclusive, the flange 42 of the packing ring 26 is provided withdiametrically opposed extensions H and 72 each provided with an aperturespaced outwardly from the outer edge of the adjacent collar 13. Theflange 3! of the packing ring 23 is provided with similar diametricallyopposed extensions 13 and 14, each of which is provided with an aperturespaced outwardly from the outer surface of the cylinder 20, and thecollar 34 is provided with diametrically opposed extensions and 16, eachof which is provided with an aperture in alignment with the aperture inthe corresponding extension of the flange 3|. A rod E1 is received atone end in the aperture in the extension TI and secured therein by a nut[8 threaded onto the externally screw-threaded end portion of the red atthe end of the packing ring 26 remote from the packing ring 3|. This rodH extends slidably through the registering apertures in the extensions13 and 15 of the packing ring 23 and collar 34, and is provided with aseries of apertures 19 extending transversely therethrough at locationsspaced apart longitudinally thereof. A similar rod 80 is received at oneend in the aperture in the extension 12 of the packing ring flange 42,and a nut 81 is threaded onto the externally screw-threaded end portionof this red at the end of the packing ring 26 remote from the packingring 23 to secure the rod in the corresponding aperture. This rod 80extends slidably through the registering apertures in the extensions 14and 16 and is provided with a series of transversely extending apertures82 spaced apart longitudinally of the rod.

Stop pins, as indicated at 83 and 84, for the rod Ti, and 85 and 86 forthe rod 80, are inserted through selected apertures in the rods and areengageable with the collar 15 and the flange 3! of the packing ring 23to adjustably limit movements of the cylinder 2! relative to thecylinder 20.

With this arrangement, it is not necessary to have a specially designedcylinder assembly for each installation, but, by adjustably limiting theelongation of the assembly, assemblies of the same size can be used forvarious installations.

' or essential characteristics thereof.

The invention may be embodied in other specific forms without departingfrom the spirit The present embodiment is, therefore, to be consideredin all respects as illustrative and not restrictive, the scope of theinvention being indicated by the appended claims rather than by theforegoing description, and all changes which come within the meaning andrange of equivalency of the claims are, therefore, intended to beembraced therein.

What is claimed is:

1. An extensile hydraulic cylinder assembly comprising a first cylinderhaving an open end and a closed end, a secondcylinder having an externaldiameter less than the internal diameter of said first cylinder receivedat one end in the open end of the second cylinder and slidably engagingthe inner surface of said first cylinder, a first packing ring securedto said first cylinder at the open end of the latter and slidablyengaging the outer surface of said second cylinder, a piston rodextending at one end into the other end of said second cylinder, asecond piston secured on said one end of said piston rod and slidablyengaging the inner surface of said second cylinder, a second packingring secured to said second cylinder at said other end of the latter andslidably engaging said piston rod, fluid conduit fittings disposed onand communicating with the interiors of said cylinders one at each endof said first cylinder and one at said other end of said secondcylinder, each of said packing rings having an external flange providedwith spaced apart extensions each having an aperture therethrough,adjusting rods extending slidably one through each extension on saidfirst packing ring and one through each extension on said second packingring, said adjusting rods being secured each at one end to said secondpacking ring and each adjusting rod having a series of aperturesextending transversely therethrough at spaced apart locationstherealong, and stop pins inserted through selected apertures in saidadjusting rods and engageable with said first packing ring to providelimit stops for movements of said second cylinder relative to said firstcylinder.

2. An extensile hydraulic cylinder assembly comprising a first cylinderhaving an open end and a closed end, a second cylinder having anexternal diameter less than the internal diameter of said first cylinderreceived at one end in the open end of the second cylinder and slidablyengaging the inner surface of said first cylinder, a first packing ringsecured to said first cylinder at the open end of the latter andslidably engaging the outer surface of said second cylinder, a pistonrod extending at one end into the other end of said second cylinder, asecond piston secured on said one end of said piston rod and slidablyengaging the inner surface of said second cylinder, a second packingring secured to said second cylinder at said other end of the latter andslidably engaging said piston rod, fluid conduit fittings disposed onand communicating with the interiors of said cylinders one at each endof said first cylinder and one at said other end of said secondcylinder, each of said packing rings having an apertured external flangeoverlying the adjacent end of the associated cylinder, collars mountedone on each cylinder at the ends of said cylinders adjacent thecorresponding packing rings, each of said collars having tapped holestherein, flange bolts extending through the anergtureszintsaidspackingring fiangesandzthneaded' into the tapped hol'esimthecorresponding col.-

lars-to securesaidipackin'gringstmsaidacylindersa each of said; packing;rings; having an; external. flange-provided: with spaced: apartextensions and.

the: collar adj'acentezsaid. firstzpacking ring-having spaced apart;extensions, each; of: said extensions having" an aperturatherethrough,adjusting rods extending siidably; one through each. extension, 1

on said: first packing: ring and-1 through; the: ex,- tensions on theassociated collar and each adiiiistiing rod having one end securedintheaperiture of a corresponding extensiononsaid' second packing ringand. each, having. a; series of. apertures extending transverselytherethrough at spaced apart locations therealong and stop pins-insertedthrough selected apertures in: said adj usting" rods and engaging saidfirst packing ringand said 8E collaradjacent, said: first packing ringto provide limit stop for movementsof said second cylinder relative tosaid first cylinder;

References Cited in. the: file of this patent UNITED STATES PATENTSNumber Name Date 214,574; McGowan Apr. 22,1879 501,426 Kampff July 11,1893 1,174,788 Winn Mar. 7, 1916 1,731,254 McNab Oct. 15, 19292,308;0'9.9 Obecny Jan. 12, 1943 2,390,702 Gailet a1 Dec. 11, 19452,442,306 McCormick May 25, 1948- FOREIGN PATENTS Number Country DateGreat Britain 1882

